教你如何用VB.net连接数据库

   初学者不防试试以下代码。。
Option Explicit On
Option Strict On
Imports Microsoft.VisualBasic
Imports System.Data.SqlClient
Imports System.Data.Common
Imports System.Data.OleDb
Imports System.Data.Odbc
Imports System.data
Public Class dataload
    '-----------------------------连接不明数据库种类代码部分---------------------------
    '**************设置要连接的数据库种类和连接方式******************
    Private stroledbprovider As String = "System.Data.OleDb" '大小写 -------更改此处可连接不同类型的数据库
    '连接数据库的信息，更改连接不同数据库信息-------"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=datapath;Persist Security Info=false"
    Private stroledbconn As String = "Provider=SQlolEDB;Data Source=localhost,10000;Initial Catalog=haofefe;user id=sa ; password=123" 'Integrated Security=SSPI"
    '*********************************************************************

    '************生成Dbproviderfactory,idbconnection,idbcommand,and idatareader********
    Dim cnfactory As IDbConnection
    Dim drcustsreader As IDataReader
    Dim cmfactory As IDbCommand
    Dim dpfactory As DbProviderFactory
    Public login As Boolean = False
    Private Sub createconn()
        Try
            dpfactory = System.Data.Common.DbProviderFactories.GetFactory(stroledbprovider)
            cnfactory = dpfactory.CreateConnection
            cnfactory.ConnectionString = stroledbconn
            cmfactory = cnfactory.CreateCommand
            cmfactory.CommandType = CommandType.Text

        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
    End Sub
    '*********************************************************

    '利用生成的连接
    '****************查询数据**************
    Public Function getsources(ByVal strcomm As String) As DataTable

        Dim i As Integer
        Try
            Call createconn() '调用生成实例
            cmfactory.CommandText = strcomm
            getsources = New DataTable
            cnfactory.Open()
            drcustsreader = cmfactory.ExecuteReader(CommandBehavior.KeyInfo)
            With drcustsreader
                For i = 0 To .FieldCount - 1
                    getsources.Columns.Add(.GetName(i))
                Next
                While .Read
                    Dim objcells(.FieldCount - 1) As Object
                    .GetValues(objcells)
                    getsources.Rows.Add(objcells)
                End While

            End With
            drcustsreader.Close()
            'getsources.Load(drcustsreader)
            Return getsources
            cnfactory.Close()
        Catch ex As Exception
            cnfactory.Close()
            Return New Data.DataTable
            MsgBox(ex.ToString)
        End Try
    End Function
    '**********************************
    '-------------------------------------------------------------------------------------------------------------
    '*******************查看已连接信息******************
    Public Sub connectionstatistics(ByVal conn As SqlConnection)
        Dim htstats As Hashtable
        Try
            htstats = CType(conn.RetrieveStatistics, Hashtable)
            Dim strstats As String
            strstats = "ServerVersion: " + conn.ServerVersion.ToString + ControlChars.CrLf
            Dim ostat As Object
            Dim strstat As String
            For Each ostat In htstats.Keys
                strstat = ostat.ToString
                If InStr(strstat, "Time") > 0 Then
                    strstats = strstats + strstat + "=" + Microsoft.VisualBasic.Format(CLng(htstats(strstat)) / 1000, "#,##0.000") + " secs" + vbCrLf
                Else
                    strstats = strstats + strstat + "=" + htstats(strstat).ToString + ControlChars.Cr + ControlChars.Lf
                End If

            Next
            MsgBox(strstats, MsgBoxStyle.Information, "Connection Statistics")
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
    End Sub
    '*(********************************************